Starter on low-pressure fluorescent tubular lamps



Aug. 16, 1949. KNQBEL 2,479,372

STARTER ON LOW-PRESSURE FLUORESCENT TUBULAR LAMPS Filed Feb. 21, 1947 2Sheets-Sheet 1 FIG.

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F. KNOBEL 2,479,372

STARTER ON LOW-PRESSURE FLUORESCENT TUBULAR LAMPS Aug. 16, 1949.

2 Sheets-Sheet 2 Filed Feb. 21; 1947 Patented Aug. 16, 1949 UNITEDSTARTER ON LOW-PRESSURE FLUORES- CENT TUBULAR LAMPS Fritz Knobel,Ennenda, Switzerland Application February 21, 1947, Serial No. 729,960In Switzerland March 2, 1946 2 Claims. (01. 315-100) My presentinvention relates to improvements in starters for low-pressure tubularlamps with series reactors or chokes, comprising a breakcontactorconnected in series with the choke and biased by a hot wire so as tobreak upon passage of current and to cause, in combination with acondenser connected between the two electrodes, an automatic arcing ofthe fluorescent tube. The objects of my improvements are first todispense with the resistor used in prior art for actuating the startingcontactor, which resistor reduces the starting potential and thusimpairs the starting operation, second to reduce the mass of the heatingwire so as to render the starter readily responsive with a view ofspeeding up the starting,

operation, and third to substantially simplify the tube construction andthe operative wiring by eliminating the heating of the electrodes and byusing only a two-wire tube connection.

I attain these and related objects by the starter and the Wiringschemes, shown by way of example, in the accompanying drawing, in whichFig. 1 is an elevation of the starter, with cover removed,

Fig. 2 a top plan view of Fig. 1,

Fig. 3 a wiring scheme of a starter on a fluorescent tube with heatedelectrodes, and

Fig. 4 a wiring scheme of a starter on a fluorescent tube with coldelectrodes,

Fig. 5 a modified wiring scheme of a starter on a fluorescent tube withheated electrodes,

Fig. 6 an elevation of a starter modified relative to that shown in Fig.1, and

Figs. 7 and 8 are cross-sections on lines VII- VII and VIII-VIIIrespectively of Fig. 6.

The starter according to Figs. 1 and 2 comprises a housing I ofinsulating material, in which all the parts are mounted. The two parts2, 3 of the break-contactor shown are riveted, together with theappurtenant connecting lugs 4, 5 into housing i. so that part 2 iselectrically connected with lug 4, and part 3 with lug 5. Further, twostuds 6, l are riveted to junction lugs 8, 9 to form an electricalconnection. A bush [0 is pivoted on stud I, and connected to anactuating arm I I. One end of a heating wire I2 is wound on bush Ill,and the other end secured to stud 6. Heating wire I2 is kept stretchedby a tension spring l3 engaging arm H, and an insulating cap 14 carriedon actuating arm II is situated in its position of rest at a certaindistance from the movable contact portion 3 of the break contactor.

In the wiring diagram according to Fig. 3, one of the two terminals l5,l6, namely terminal 15,

Jr: is connected with junction lug 8 of heating wire l2, while a circuitis completed from the other junction lug 9 of heating wire l2 overthermofuse ll, reactor coil 18, terminal l3, heating electrode 20 of thefluorescent tube 2i, terminal 22, junction lug 5, break-contactor 3, 2,junction lug 4, terminal 23, the other heating electrode 24 01' tube 2|,terminal 25, and the second reactor coil 26 to the other terminal IS, astarting condenser 21 being interposed between the terminals l9 and 25,which at the same time serves for radio dehumming.

When engaging the starter, the electrodes 20, 24, are heated at once,and heating wire I2 is expanded, thus turning actuating arm H indirection of the arrow shown in Fig. 1. Actuating arm H, after coveringa certain non-operative path, breaks contactor 2, 3 by virtue ofinsulating cap 14 biasing contactor portion 3, thus breaking thecircuit, and heating wire l2 rapidly cools off again. Thebreak-contactor is again closed, and such alternation is continued,until the fluorescent tube has been started. Current, now, flowscontinuously from network terminal I5 over lug 8, heating Wire [2, lug9, thermo-fuse ll, coil l8, terminal l9, electrode 2|], through tube 2|,electrode 24, terminal 25 and coil 26 to network terminal l6. Thus acurrent flows continuously through the heating wire l2, and breakcontactor 2, 3 is held broken.

The starter described, in contra-distinction to starters of prior artcomprising glow relays or bi-metal contactors, possesses the advantagethat no resistor connected parallel to the fluorescent tube is providedfor actuating the starting con-' tactor, which resistor reduces thestarting potential and thus impairs starting. Further, the mass of theheating wire used is so small that the starter responds very quickly,and starting therefore, takes place rapidly.

In the wiring diagram according to Fig. 4, a fluorescent tube 28 withcold electrodes 29, 30 is used, which is connected to the terminals 3|,32. Further, a choke or reactor coil 33 is provided for. When switchingon this starter, a ircuit is completed from network terminal l5 over hotwire I 2, thermo-fuse ll, choke coil 33, and break-contactor 3, '2 tonetwork terminal I-B. Contactor 3, 2 thus is alternatingly made andbroken, as in the first example, until an arc strikes along tube 28 bythe action of the starting condenser 21 upon which a continuous flow ofcurrent takes place from network terminal l5 over hot wire [2,thermo-fuse ll, choke coil 33, terminal 32, electrode 30, tube 28,electrode 29, and terminal 3| to network terminal l6; andbreak-contactor 2, 3 is held broken.

The example according to Fig. 4, as will be ape preciated, substantiallysimplifies the tube construction and the wiring scheme, in that heatingthe electrodes may be dispensed with and only a two-wire connectipn. isrequired for the tube.

The example according to Fig. 5 difiers from that shown in Fig. 3 inthat only one reactor 34 is provided for, and that heating wire I2 iscon this is a point of particular interestoncand the Heating wire I2thus may be made sufiis.

same starter may be used for all types of tubes .or instruments havingdifferent current ratings, an adaption only being necessary insofar asthe number of turns between the end of reactor 34 and the -tapping forthe heating wire is chosen such'that the-voltage'arising on the heatingwire at-ratd current correspond to the requirements Iorea'chtype-ofinstrument.

' Thefstarter accordingto Figs.- 6-8 differs from thatshown in Fig, '1in that the two studs 6, 1 supporting heating wire-l2 are-mounted bymeans of a metaltransverserail 35. Stud 6 is riveted we railffiinnlx'whereas lug- 8 is secured to housing l 'by-a-rivet 35; Anextension 31 of heating wire-121s passed through housing I and solderedto ,lug 8. Stud 1, however, at the same time serves ionconnectingrail35' tohousing I, passing throughtheilatterand being-riveted to lug 9. Aninsulating-ring .38 is disposed between stud 7 and rail '35; Bysuch-arrangement of a metal transverse rail,- fh'eating wire: l2 becomes7 independent bran-expansion of' housing I which expansion maybeconsiderable for a Bakelite housing for eiia-mple' d Whatfclaimand-desire tosecure by Letters Patentis: V I

'1: w A low-pressure fluorescent tube starter comprising an insulatinghousing, a break-contactor mountedin-the-latter, two studs, a metallicrail secured inthesaid-housing by one of the said 7 '4 studs forindependent expansion, a pair of lugs for electrical connection mountedoutside the said housing and secured to said studs respectively, awasher insulating one of the said studs from said rail, a bush rotatableon one of the said studs, a heat-responsive wire disposed between thesaidstuds and having one end secured to said bush, a spring-loaded armSecured to said bush, and an insulating cap mounted on the free end ofsaid arm; the whole in such combination that the said contactor isbroken through the swinging action-of thesaid arm after the said Wirehas been heated, so that the current will pass through thefluorescent-tube.

2. A starting device for a low-pressure fluorescent tube including-apair of tube electrodes, comprising-in combination an insulating housing,.-.ajbreak-oontactor mounted in the latter and connected in serieswith said electrodes, two studs, a metallic rail secured in the saidhousing by one of the said studs for independent expansion; a pairof-lugs for electrical connection mounted outside; the said housing andsecured 'to-said' studs respectively, a washer il'lS'll? lating onepfthe said studs from said rail, a bush rotatable-on one of-the saidstuds, a heat-responslve wire disposed between the said. studs andhavingeone endsecured to said bush, a springloaded arm securedto saidbush, an insulating cap mounted on-the :freeend of said arm, a single,choke in circuit for said electrodes and means for connecting oneterminal of said heat responsive Wire to difierent intermediate pointson said choke for the purpose ofadapting one and the wint r Starter totubes ofdiiierent current ratings.

' FRITZ KNOBEL. I

REFERENCES? CITED The -f o ow .n r referen es. are of re rd in the fileof this. patent:

g STATES- PATENTS Number Yost sin in -U.- .sv-e- 0 1942

